136 Effects of Alkalies, etc., on Eggs of Echinus. 



of the Liverpool Cancer Eeseareh, of examining the appearances represented in 

 figs. 29 and 30 under a specially high magnification of about 3000 diameters. 



The magnification was obtained with a 10-inch tube, 3 mm. Zeiss 

 apochromatic objective, 27 compensating ocular, and with monochromatic 

 green illumination. Messrs. Moore and Walker have pointed out to us that 

 these bodies, which appear as described in the text when seen with an 

 ordinary -jig-inch oil immersion, are, when seen with the 3000 diameter 

 magnification, really spheroidal bodies consisting of an inner mass or vesicle 

 which scarcely stains at all, over which ramify filaments of deeply staining 

 chromatin. Further examination with this magnification also demonstrates 

 that the chromosomes represented as dots in fig. 28 are, in reality, also 

 vesicular chromosomes. Even with the -jij-inch oil immersion we had been 

 able to see a well-marked black line around the periphery of each dot, but 

 had been unable to determine whether or not this was merely an optical 

 effect. The 3000 diameter magnification, however, clearly shows that the 

 structure is the same as that of the larger masses in figs. 29 and 30. 



It is interesting that these minute chromosome masses occur upon the 

 spindle in exactly similar fashion to the normal rod-shaped chromosomes, and 

 that wherever they occur there is a diminution in the number of chromo- 

 somes. In many cases an occurrence of both rod chromosomes and spheroidal 

 chromosomes is observable upon the same spindle as if conversion had only 

 partly taken effect. 



Where conversion of the entire number of chromosomes into the spheroidal 

 variety is seen upon the spindle, the number of such chromosomes is usually 

 approximately half the normal number, as in fig. 28. But when they are 

 found after separation has taken place, as in figs. 29 and 30, the number 

 is very variable, and as the number diminishes there is a corresponding 

 increase in size in the individual chromatic vesicles. 



We are informed by Messrs. Moore and Walker that bodies presenting a 

 similar appearance are seen in malignant growths, and also under other 

 pathological conditions, and in certain normal tissues. 



The question of the relationship, if any, of the diminution in number when 

 such spheroidal chromosomes are formed, to the reductions occurring in 

 normal maiotic division, and in cancer cells, we prefer to leave at the present 

 entirely open, since we have no evidence that the diminution in number is 

 effected by the same means ; and we merely point out the diminution of the 

 number of chromosomes upon the spindle as a result of increasing the 

 alkalinity of the medium, as an interesting and suggestive fact.] 



